Woodstock 99 (although the entire concert was AMAZING, Korn did play a nice long set which I really thought was awesome)

and once during a concert in 2005 with 10 Years and Mudvayne supporting.

It's a great show, you won't be disappointed. Their fans are awesome and they do try to keep a lot of fan favorite songs in their sets. They didn't have time to sign albums however during my 2 times seeing them, that's the only thing I didn't like but ehh, their busy people I figure.